Adjustable eccentric



Dec. 10, 1940. cs.v w Kan-:GH

ADJUSTABLE ECCENTRIG Filed March 18, 1940 ATTORNEY.

Patented Dec. 10, 1946` UNITED STATES PATENTA @FFiCE 8 Claims.

This invention relates to improvements in adjustable eccentrics.

It frequently happens in the designing of machinery that it is highly desirable to effect a variation in stroke of some reciprocating member While the machine is operating and for this purpose various designs have been made and patented by means of which an eccentric can be adjusted during operation.

It is the object of this invention to produce an eccentric that can be readily adjusted while the machine is operating and which shall be of simple and substantial construction.

Another object is to produce an eccentric of such construction that the parts will be held rigidly in adjusted position and which is free from lost motion.

A further object is to produce an eccentric that can be adjusted in either direction by simply retarding a handwheel that is accessible from the end of the shaft. v

The above and any other objects that may become apparent as this description proceeds are y attained by means of a construction and an arrangement of parts that will now be described in detail and for this purpose reference will be had to the accompanying drawing in which the invention has been illustrated in its preferred form, and in which:

Figure 1 is a diametrical section taken on line I--I, Figure 2;

Figure 2 is a section taken on line 2-2, Figure 1;

Figure 3 is a section taken on line 3 3, Figure 2; and

Figure 4 is a section similar to that shown in Figure 1, but illustrating a slightly modified form of construction.

On the drawing reference numeral 5 desigvided with axially aligned tubular extensions 6 that may be of any desired length and may terminate in outwardly extending flanges 1 that are provided with angularly spaced threaded openings 8 for the reception of cap screws 9.

The hub has an enlarged chamber I0 at its middle point. From one side of the hub a tubular projection Il extends radially and this is provided with a cylindrical opening l2 whose axis intersects the axis of the openings in tubular extensions 6. Diametrically opposite from the projection Il and in axial alignment with opening I2, an opening I3 is provided. A body cap I4 is provided with a cylindrical portion I5 that ts the opening I3 with a snug fit and is also nates the hub body as a whole. The hub is prohas been Vdesignated by reference numeraly 2|. g

1t will be observed thatthe body cap projects intofthe central chamber in the hub and terminates a short distance below the center thereof. The opening I8 is closed by a transverse wall 22 that is provided with a central opening 23 for the reception of a cylindrical portion of pin 24 which is provided with a cylindrical section 25 to which a Boston bevel gear 26 is attached. An anti-friction thrust bearing 21 is provided between the gear 26 and the inner surface of end wall 22. Pin 24 extends through the radial opening I2 and is of somewhat smaller diameter than the latter and isprovided with threads 28, preferably square threads. A nut 29 is threadedly connected with the lower end of the rotatable pin and serves to hold the same from transverse movement relative to the wall 22. A hollow stub shaft 30 extends into the tubular extension 6 at the right when viewed as in Figure 1, and this shaft is provided with an outwardly extending ange 3| that is attached thereto by welding as indicated by reference numeral 32. Flange 3| is perforated for the reception of the cap screws 9 by'means of which it is secured to the end 1 of the hub. A rod or pinion 'shaft 33 is positioned centrally of the stub shaft and journaled in bearings 34 and 35. Secured to the inner end of shaft 33 Vis a pinion B that meshes with gear 25. Attached to the outer end of the pinion shaft is a handwheel 31. This has been shown as held in place by means of a set screw 3&3. Bearing 35' is providedwith a cylindrical opening that extends inwardly from its outer endand in which is positioned a helical comn pression 'spring 39. This spring engages a ball Il@ which in turn engages the inner surface .of the handwheel hub. lThe latter is provided withl a depression 4I that receives the ball when the handwheel is in one position and which serves as a releasable detent.

,It will now be seen that whenever the handwheel 3l is rotated relative to shaft 3l! it will imparta corresponding rotary movement to the gear 26 and to the pin 24 that is nonrotatably attached to the gear. A stub shaft 42 is attached to the other end of the hub in the same manner as stub shaft 3E) and this shaft may be either hollow or solid. In Figure 1, stub shaft 42 has been shown as solid, but can be replaced by a tubular shaft when desired.

An annular eccentric disk comprising the two parts 2U and 2l are respectively provided with inwardly extending plugs I9 and 43 that are in axial alignment and which engage respectively in openings I8 and I2. Both of these plugs have been shown as tubular and plug 43 has its opening provided with threads for the reception of the threaded portion 28 of the rotatable pin 24. The two eccentric disk members are provided with inwardly extending lugs 44 through which bolts 45 extend for the purpose of securing the two parts in assembled position. When the eccentric disk members are in position as shown in Figures 1, 2 and 3, they can be shifted transversely with respect to the axis of the stub shaft by turning the pinion shaft 33 so as to rotate the threaded pin 24 in the plug 43.

The periphery of the eccentric disk is provided with a depressed bearing surface 46 in which the eccentric strap 41 is positioned. 'I'he eccentric strap comprises an upper and lower portion, each provided with outwardly projecting lugs 48 that have openings for the reception of bolts 49 which serve to hold the strap in position on the eccentric. The lower half of the eccentric strap is provided with a downwardly extending tubular projection 5i) whose opening is threaded for the reception of the threaded upper end of the connecting rod 5|. A lock nut 52 serves to hold the connecting rod in place. The connecting rod may be attached to any mechanism that is to be given a reciprocatory motion and in the specific embodiment of this invention the connecting rod is attached to the diaphragm of a diaphragm pump which has not been shown as it is obvious that it can be employed wherever a variable reciprocatory motion is desired.

When a single handwheel is employed, as in the embodiment illustrated in Figure 1, one of the adjustments can be effected by merely grasping the handwheel and holding it against rotation, whereby it will rotate relative to the stub shaft. If the adiustrnent'requires the wheel to be moved in the same direction as the shaft, it must be turned faster than the shaft so as to rotate relative thereto. Since an apparatus of this kind is usually employed in machinery where comparatively slow rotary motion is needed adjustments in both directions can readily be effected.

Where higher speeds are used and where greater convenience is desired, the solid stub shaft 42 can be replaced by a tubular stub shaft 3U as shown in Figure 4 and two pinion shafts 33 employed. It is apparent from Figure 4 that to effeet the same adjustment of the eccentric the two pinion shafts 33 must be rotated in opposite directions and therefore both adjustments can be effected by merely holding the handwheel 31 on the shaft that will give the desired adjustment.

In Figure 4 a slightly modified form of construction has been illustrated which will now be described.

Instead of employing a hub having lateral tubu lar extensions 6 into which the shaftextends and a body cap like that indicated by reference numeral i4 which must be held in place by means of cap screws a construction is employed in which a shaft 30 extends through the hub and is provided with a diametrical opening. To this shaft is secured a hub Il which is formed from a short piece of pipe having a diametrical opening adjacent one end through which the tubular shaft 30 extends. The opening in hub Il is positioned to register with the diametrical opening and the .hollow shaft and the two parts are secured by welding. The openings in the hub and in the shaft 33 at the end of the hub nearest the center of the shaft, are threaded for the reception of threaded cap 53 which correspond in function to body cap I4 shown in Figure 1. Cap 53 is hollow and its bottom is provided with a bearing 23 for the reception of the cylindrical portion of threaded pin 24. The pin is provided with the same bevel gear shown in Figure 1 which can be rotated by means of the shafts 32 which project in opposite directions. l

The construction shown in Figure 4, aside from the fact that the hub is made from a piece of pipe Welded to the shaft is otherwise substantially identical with the construction shown in Figures l, 2 and 3. The tubular extensions E shown in Figure l have been dispensed with and the construction shown in Figure 4 but this is merely a change in degree and not in function.

With the construction described above, the gear ratio and the pitch of threads 28 can be so calculated that one turn of the pinion shaft will make a predetermined difference in the stroke. The number of turns can be easily calculated due to the detent ball which drops into a depression at each turn of thevshaft. Various other changes may also be made within the scope of the appended claims. The working parts are all enclosed in a grease tight housing so that they may be properly lubricated.

By eliminating the eccentric strap and increasing the weight of the eccentric disks, this mechanism can be used as a vibrator whose effect can be adjusted by the means shown to obtain the most desirable results.

From the above description it will be apparent, that the eccentric described and illustrated is of a simple and substantial construction, that it can be manufactured at ai comparatively low cost, and that it can be readily adjusted during operation.

Having described the invention what is claimed as new is: l

1. An adjustable eccentric comprising in combination, a hollow hub having a radial tubular projection and an axial opening, theaxes of the openings intersecting at right angles, a threaded pin in axial alignment with the radial opening and of smaller external diameter .than the Yinterior thereof, a bearing for one end of they pin, means comprising a bevel gear secured to the pin and a rod rotatably mounted in the axial opening for rotating the threaded pin, and a twopart annular eccentric provided with a radial, inwardly-extending, axially aligned plug, positioned to engage in the radial opening, said plug having a threaded opening for the reception of the threaded pin whereby when the pin is rotated the eccentric will be moved transversely vof the hub.

2. An adjustable eccentric comprising, in combination, a hollow hub having radially extending aligned tubular projections, the hub having an axial opening `extendingat right angles to the axis of the tubular projections, a bearing block positioned in one of said projections, a threaded pin having one end rotatably mounted in the bearing block, a tubular shaftpositioned in the axial opening, a bearing positionedin the tubu-v lar shaft, a rod journaled in the bearing, .a bevel gear on the end of the rod, a bevel gear carried by the pin for cooperation with the gear on the rod, an annular two-part eccentric disk enclosing the hub, each part having Va radial plug extending inwardly, the plugs being positioned to project into the radially extending tubular projections, one of said plugs having a threaded opening for the reception of a threaded pin, whereby when the latter is rotated, the eccentric will be moved transversely of the hub.

3. An adjustable eccentric comprising in combination, a hollow hub having an axial opening for the reception of a hollow shaft, the hub wall being also provided with a radially extending tubular projection, the axis of the opening in which intersects the axis of the axial opening, a bearing block secured in one end of the tubular projection, a pin journaled in the bearing, the pin being of smaller diameter than the opening in the tubular projection and threaded, a hollow shaft secured in the axial opening, a rod extending through the hollow shaft, bearing blocks in the shaft, in which the rod is rotatably mounted, the pin and the inner end of the rod having cooperating gears for effecting simultaneous rotation and a two-part annular eccentric disk surrounding the hub, each part having a radial inwardly extending plug adapted to enter an end of the opening in the tubular projection, one of said plugs having a threaded opening for reception or" the threaded pin, whereby when the latter is rotated the eccentric disk will move transversely to vary its eccentricity.

4. An adjustable eccentric comprising a hollow hub having an axial opening provided with a central chamber and with diametrioally opposed tubular projections, a bearing positioned in one of the openings, .a pin rotatably mounted in the bearing, means for holding the pin from longitudinal movement in the bearing, the pin being provided with threads, a hollow shaft positioned in the axial opening, a rod rotatably mounted in the shaft, a bevel gear carried by the pin, a bevel pinion carried by the inner end of the rod and operatively associated with the bevel gear on the pin whereby the latter will be rotated whenever the rod is turned relative to the shaft, .and a two-part annular eccentric disk surrounding the enlarged portion of the tubular hub, each of the parts having a radially extending, inwardly projecting plug adapted to enter one of the tubular projections, one of said plugs having a threaded opening for the reception of the threaded pin whereby when the latter is rotated, the eccentric disk will be moved transversely of the hub.

5. An adjustable eccentric comprising in cornbination, a hollow hub having .an axial opening extending therethrough, the central portion being provided with a chamber, the wall of the chamber having oppositely extending tubular projections provided with radial openings having a common axis that intersects the axis of the .axial opening, a bearing secured in one of the tubular projections, a pin journaled in the bearing, one end of the pin extending into the other radial opening, the outer surface of the pin being threaded, a two-part annular eccentric disk having radial plugs extending inwardly, the plugs being in axial alignment and positioned to enter the openings in the tubular projections, one of the plugs having a threaded opening for the reception of the pin, and means comprising a rod extending into the hub through the axial opening for rotating the plug whereby the eccentricity of the eccentric disk will be varied with respect to the hub by turning the rod.

6. An adjustable eccentric comprising in combination, an elongated hollow hub having an axial opening extending therethrough, the central portion having an enlarged chamber, the wall of the chamber having oppositely extending projections provided with radial openings having a common .axis that intersects the axial opening, a hollow shaft having one end positioned in one end of the last mentioned opening, a rod rotatably mounted in said shaft, a bevel pinion secured to the inner end of the rod, a handwheel secured to the outer end., of the rod, a spring pressed detent positioned. between the outer bearing and the handwheel to resist accidental rotation of the rod, a bearing positioned in one of the 'radial openings, a threaded -pin rotatably mounted in the last mentioned bearing, the pin and bearing having cooperating means for holding the pin from longitudinal movement with respect to the bear-ing, a bevelV gear attached to the pin in cooperative engagement with the bevel pinion on the rod, the pin extending into the opposite radial opening and being of a smaller diameter than the latter, a two-part annular eccentric disk enclosing the enlarged portion of the hub, each part having an inwardly-extending radial plug positioned to enter one of the radial openings, one of said plugs having a threaded opening for the reception of the threaded plug whereby when the plug is turned the eccentric will move transversely of the hub thereby varying its eccentricity.

7. A device in accordance with claim 6 in which two tubular shafts extend in opposite directions from the hub'and in which a rod is rotatably mounted in each shaft and provided with a bevel pinion for engaging the bevel gear on the pin and with a handwheel accessible at the end of each shaft', whereby the threaded pin can be rotated in either direction by retarding the rotation of one or the other of the rods.

8. An adjustable eccentric comprising in combination, a tubular shaft having a diametrical opening, an elongated tubular hub surrounding the shaft, said hub having a transverse opening for the reception of the shaft and the second opening extending at right angles to the first, the hub projecting unequal distances from the center of the shaft, a hollow bearing block positioned in the end of the hub opening nearer the center of the shaft, a threaded pin journaled in the bearing and extending into that part of the opening on the other side of the shaft center, the pin being of smaller diameter than'the opening, a two-part eccentric disk, each part having a radial plug each plug being positioned to enter an end of the tubular hub, one of said plugs having a threaded opening for the reception of the pin, means for securing the two parts of the eccentric disk together, a gear carried by the pin, a rod mounted for rotation in the shaft,V

a gear member secured to the inner end of the rod for operative engagement with the gear on the pin, and means accessible from the outside of the shaft for rotating the rod relative thereto while the shaft is rotating.

GEORGE W. KRIEGH. 

